What does an overwhelming presence of rotifers in sludge indicate?

An overwhelming presence of rotifers in sludge typically indicates that the sludge is old. Rotifers are a type of small multicellular organism that often thrive in environments rich in organic matter and bacteria, conditions commonly found in aging sludge. As sludge matures, its biological community evolves, and rotifers become a dominant part of this ecosystem, reflecting the aging process. Their presence is a sign of a stable and established microbial community, indicating that the organic material has been processed and broken down over time. This characteristic is not associated with fresh sludge, which would contain a different microbial makeup, and it does not suggest high acidity, which would be detrimental to rotifer populations. Consequently, the presence of rotifers serves as an important indicator of sludge condition and age.